Technical Field
The present invention relates to an organic light-emitting display device and a method of manufacturing the same, and more particularly, to an organic light-emitting display device and a method of manufacturing the same, which may simplify a process by reducing the number of masks when forming the organic light-emitting display device, and may increase reliability when forming an organic light-emitting layer by a solution process.
Discussion of the Related Art
An image display device, which realizes various pieces of information on a screen, is a core technology of the information and communication age, and is being developed in the direction of becoming thinner, lighter, more portable, and having higher performance. In response, as a flat panel display device that is thinner and lighter than a cathode ray tube (CRT), for example, an organic light-emitting display device, which controls the amount of light emitted from an organic light-emitting layer to display an image, is in the spotlight.
In an organic light-emitting display device, a plurality of pixels is arranged in a matrix form to display an image. Here, each pixel includes a light-emitting element, and a pixel drive circuit including, for example, a plurality of transistors and storage capacitors to independently drive the light-emitting element. Here, each light-emitting element includes an organic light-emitting layer between a first electrode and a second electrode.
The organic light-emitting layer is configured such that a plurality of layers such as, for example, a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer are stacked one above another. The organic light-emitting layer has been manufactured by depositing these layers via thermal deposition in different process chambers. However, this related art method of manufacturing the organic light-emitting layer entails high manufacturing costs and a complicated manufacturing process and is difficult to use to realize a large-area mask.
In order to solve the problems, a technique of forming an organic light-emitting layer using a solution process such as, for example, ink-jet printing or nozzle coating has been proposed.
The organic light-emitting layer formed using the solution process undergoes a pile-up phenomenon in which the organic light-emitting layer is relatively slowly cured in the edge portion thereof and begins to be cured from the central portion thereof, thus causing the edge portion of the organic light-emitting layer to be thicker than the central portion. In order to solve this problem, a technique of forming a bank layer, which defines a pixel portion, in double layers so that a lower layer forms a hydrophilic bank and an upper layer forms a hydrophobic bank in order to reduce the difference in thickness between the central portion and the edge portion of the organic light-emitting layer has been proposed. However, when the bank layer is formed to have a double-layered structure, this may cause a complicated process and high manufacturing costs, and may also cause, for example, separation of the upper bank layer due to the low adhesive strength between the hydrophilic lower bank layer and the hydrophobic upper bank layer.